1. Field of the Invention
The present invention pertains to a protein beverage and protein beverage concentrate, and to methods of making the protein beverage and protein beverage concentrate.
2. Brief Description of the Background Art
This section describes background subject matter related to the disclosed embodiments of the present invention. There is no intention, either express or implied, that the background art discussed in this section legally constitutes prior art. Moreover, this brief description is not intended to fully describe the subject matter of this art, the reader is invited to more thoroughly examine the background to better understand what is disclosed.
Milk contains two major protein fractions, casein, which may provide about 80% by weight of the total protein, and whey protein, which may provide about 20% by weight of the total protein. The whey protein fraction is the protein fraction which may remain soluble when the casein fraction is coagulated (such, for example, as by either enzyme or acid) and separated as cheese curd. Whey protein may include several protein fractions, including, for example, β-lactoglobulin, α-lactoglobulin, Lactalbumin, immunoglobulins (such as IgG1, IgG2, IgA, and IgM, for example), lactoferrin, glycomacropeptides, and lactoperoxidase.
Compared to casein and untreated soy (e.g., aqueous soy protein isolate; unacidified soy), whey proteins may be highly soluble. Whey proteins may be the least soluble at typically about pH 4.5 to about pH 5.5, which may be the isoelectric point (the pH at which the net electrical charge is zero) for whey protein. In higher acid systems with a pH less than about 4.5, such as in many carbonated beverages, the acid solubility of whey proteins may be especially important; however, protein precipitation may occur during the mixing period when the pH of the whey protein, which typically has a pH of about 6 to about 7, transitions through the zone of isoelectric points. Protein solubility may be affected by heat, and therefore the elevated temperatures experienced during pasteurization may also negatively affect solubility and fluidity resulting in protein precipitation or gelation.
Whey protein may have a higher biological value and/or protein digestibility corrected amino acid score (PDCAAS) than casein. The physical properties of whey proteins in the digestive tract may be quite distinct from the properties of casein. Caseins may form curds within the stomach, which curds may be slow to exit from the stomach and which curds may increase their hydrolysis prior to entering the small intestine. Alternatively, whey proteins may reach the jejunum almost immediately; however their hydrolysis within the intestine may be slower than that of caseins, so their digestion and absorption may occur over a greater length of the intestine.
The protein efficiency ratio (PER) of a protein source measures the weight gain of young animals per gram of protein eaten over a given time period. Any protein having a PER of 2.5 is considered good quality. Whey protein is considered to be a nutritionally excellent protein, as it has a PER of 3.2. Casein has a PER of 2.5, while many commonly used proteins have a PER of less than 2.5, such as soy protein (PER 2.2), corn protein (PER 2.2), peanut protein (PER 1.8), and wheat gluten (PER 0.8). The higher PER of whey protein may be due in part to the high level of sulfur-containing amino acids in whey protein. Such higher level may contribute to whey protein's ability to enhance immune-function and antioxidant status.
Whey protein is a rich source of branched chain amino acids (BCAAs), containing the highest known levels of any natural food source. BCAAs are important for athletes, since, unlike the other essential amino acids, they are metabolized directly into muscle tissue and are the first amino acids used during periods of exercise and resistance training. Thus, intake of BCAAS can be beneficial before periods of exercise and resistance training, or during recovery after periods of exercise and resistance training BCAAS are also important for the elderly, those recovering from illness or surgery, those involving heavy physical work, and those enduring times of stress, as well as athletes or sports participants. Leucine may be important for athletes, the elderly, those recovering from illness or surgery, those involving heavy physical work, and those enduring times of stress, as it may play a key role in muscle protein synthesis and lean muscle support and growth. Research suggests that individuals who exercise benefit from diets high in leucine and may have more lean muscle tissue and less body fat than individuals whose diet contains lower levels of leucine. Whey protein isolate may have approximately 45% by weight more leucine than soy protein isolate.
Whey protein is available in several forms, with preparations which may range from about 1% to about 99% whey protein. Whey protein preparations may be in an aqueous form created by the removal of casein, but often takes several other forms, such as, for example, but not by way of limitation, a whey protein extract, whey protein concentrate, whey protein isolate, or whey protein hydrolysate.
Whey protein concentrate may be prepared by removing sufficient non-protein constituents from whey by membrane filtration, so that the finished dry product may be selected to contain whey protein at a given concentration which may range from about 25% by weight to about 89.9% by weight protein.
Whey protein isolate may be obtained by removing sufficient non-protein constituents from whey by membrane filtration or ion exchange absorption, so that the finished dry product may contain about 90% by weight or more whey protein, and little, if any, fat, cholesterol, or carbohydrates (e.g., lactose). Prior to concentration and spray drying, aqueous whey protein isolate (WPIaq) may have a whey protein concentration of about 1% by weight to about 35% by weight, and may also be essentially free of fat, cholesterol, and carbohydrates.
Whey protein hydrolysate is a whey protein preparation which may have been subjected to enzymatic digestion with a protease enzyme or limited acid hydrolysis, or a suitable mechanical breakage of peptide bonds to form smaller peptides and polypeptides. The protein concentration of the whey protein hydrolysate may be dependent upon the starting material. For example, a whey protein hydrolysate prepared from an 80% by weight whey protein concentrate may have an 80% by weight protein concentration, and a whey protein hydrolysate prepared from a 90% by weight whey protein isolate may have a 90% by weight protein concentration. Not all hydrolyzed whey proteins may behave alike in a food formulation, and thus one hydrolyzed whey protein may not be interchangeable with another. The functional and biological properties of whey protein hydrolysates may vary depending upon factors, such as degree of hydrolysis and which protease enzyme is used for hydrolysis.
Although hydrolysis of whey protein may lead to increased solubility, it may also negatively impact the taste. Whey protein typically has a fresh, neutral taste which may allow it to be included in other foods without adversely affecting the taste. However, hydrolysis of whey protein may result in a very bitter taste, which may impose a practical limit on the amount of whey protein hydrolysate that can be used in a food product. Therefore, a high protein beverage made with whey protein hydrolysate may require a large amount of sweeteners, or bitter masking agents to overcome the bitter taste. However, such a large amount of sweetener may not be desirable to many consumers or the bitter aftertaste of the high protein beverage may be difficult or impossible to mask to a satisfactory extent for some applications.
Whey protein contains all of the essential amino acids, and therefore, is a high quality, complete source of protein, where complete means that whey protein contains all the essential amino acids for growth of body tissues. Since whey protein is available in forms containing little fat and carbohydrates, it may be a particularly valuable source of nutrition for athletes and for individuals with special medical needs (e.g., lactose intolerant individuals), the elderly, those recovering from illness or surgery, those involving heavy physical work, and those enduring times of stress, and may be a valuable component of a diet program. Further, since whey protein may contain biologically active proteins such as the immunoglobulins, lactoperoxidase, and lactoferrin, whey protein may provide advantages over other protein sources such as soy protein. Carbonated protein beverages are refreshing products that may provide whey or other desirable proteins to the consumer, e.g., athletes, for individuals with special medical needs (e.g., lactose intolerant individuals), the elderly, those recovering from illness or surgery, those involving heavy physical work, those enduring times of stress, and those interested in weight control, but these carbonated products are to be consumed before or after periods of exercise or intense work, but not during periods of exercise or intense work, as consumption of such carbonated beverages during exercise or intense work may have negative effects such as nausea and vomiting.
Milk and dairy based products may provide an excellent environment for the growth and propagation of a wide spectrum of microorganisms. Pasteurization, by the application of heat for a specific time, has been the traditional method used for more than 100 years to prevent or reduce the growth of microorganisms and to increase the shelf life of milk and dairy based products. Pasteurization may not kill all microorganisms in milk and dairy products. However, it does reduce their numbers so they are unlikely to cause illness in the people consuming those products. Non-sterile dairy products, including pasteurized dairy products, typically have a shelf life that is limited to a short period of time such as a few weeks due to spoilage from the growth of microorganisms which survived pasteurization or were introduced by post-processing microbial contamination.
The traditional method of pasteurization was vat pasteurization, which involved heating the liquid ingredients in a large vat or tank for at least 30 minutes. Variations on the traditional pasteurization methods have been developed, such as, high temperature short time (HTST) pasteurization, ultra pasteurization (UP) processing, and ultra high temperature (UHT) pasteurization. These variations on the traditional pasteurization method use higher temperatures for shorter times, and may result in increased shelf lives which may exceed 3 months without refrigeration. However, regardless of the pasteurization method used, stabilizers and preservatives may often be needed to improve the stability of pasteurized products.
Thermal processing by any pasteurization method may have detrimental effects on the organoleptic and nutritional properties of milk and dairy based products. Thus, there may be a need for more non-thermal methods of extending shelf life, which will not significantly decrease or alter the organoleptic and nutritional properties of milk and dairy based products.
One alternative to pasteurization may be high pressure processing (HPP), which may be especially suited to high acid content foods. HPP is a food processing method where food products may be exposed to elevated pressures, in the presence or absence of heat, to inactivate microorganisms. HPP may also be known as high hydrostatic pressure processing (HPP) and ultra high-pressure processing (UHP).
Non-thermal HPP may be used to extend the shelf life of milk and dairy based products without detrimentally altering the organoleptic and nutritional properties of these products. Non-thermal HPP may eliminate thermal degradation, and may allow for the preservation of ‘fresh’ characteristics of foods. Shelf lives similar to those of pasteurized products may be achieved from HPP.
HPP of a milk or dairy based product may be achieved by placing the product in a container within a water (or other pressure-transmitting fluid) filled pressure vessel, closing the vessel, and increasing the pressure exerted upon the container by pumping more water into the pressure vessel by way of an external pressure intensifier. The elevated pressure may be held for a specific period of time, then it may be decreased. Pressure levels of about 600 MPa at 25° C. may typically be enough to inactivate vegetative forms of microorganisms, such as non-spore forming pathogens, vegetative bacteria, yeast and molds.
HPP is explained in more detail in U.S. Pat. No. 6,635,223 B2 to Maerz, issued Oct. 21, 2003, entitled “Method for inactivating microorganisms using high pressure processing”, wherein a method for inactivating microorganisms in a product using high pressure processing is disclosed. The method involves the steps of packing the product in a flexible container, heating the product to a pre-pressurized temperature, subjecting the product to a pressure at a pressurized temperature for a time period; and reducing the pressure after that time period. The method may also further comprise an additional step of subjecting the product to a predetermined amount of oxygen for a time interval. These methods may be applied to food, cosmetic or pharmaceutical products.
Carbon dioxide (CO2), a naturally occurring component of raw milk that decreases as raw milk is exposed to air or is pasteurized, is known to have antimicrobial properties. CO2 results in minimal harm in foods. Therefore, it is a suitable agent for inhibiting food spoilage microorganisms. Currently, there are at least three general mechanisms known by which CO2 inhibits microorganisms. These mechanisms, outlined briefly below, are discussed in more detail in an article by J. H. Hotchkiss et al., in Comprehensive Reviews in Food Science and Food Safety 2006; 5: 158-168, titled: “Addition of carbon dioxide to dairy products to improve quality: a comprehensive review”.
One mechanism by which CO2 may inhibit microbial growth may simply be by the displacement of O2 by CO2. Another mechanism by which CO2 may inhibit microbial growth may be by lowering the pH of the food by the dissolution of CO2 and formation of carbonic acid in the aqueous phase of the food by the following equilibrium reactions: H2O+CO2H2CO3H++HCO3−2H′+CO32−. The third mechanism by which CO2 may inhibit microbial growth is by a direct effect of CO2 on the metabolism of microorganisms.
The last mentioned mechanism, the direct antimicrobial effect of CO2 on the metabolism of microorganisms, may be the result of changes in membrane fluidity due to CO2 dissolution, reductions in intracellular pH, and direct inhibition of metabolic pathways, including decarboxylation reactions and DNA replication. CO2 is quite lipophilic, which may allow for it to concentrate within the lipid membrane of bacteria, or to pass through the lipid membrane and to concentrate within the bacterial cell lowering intracellular pH. CO2 may also interfere directly with required enzymatic processes within microorganisms, such as gene expression.
Published European patent application. EP 0812544 A2 of Henzler et al., published Dec. 17, 1997, entitled “Method for preparing dairy products having increased shelf-life”, describes a method for preparing dairy products having increased shelf-life by incorporating CO2 into such products, comprising contacting a fluid milk fraction of a dairy foodstuff with CO2, mixing the fluid milk fraction and CO2 into a solution, and subjecting the solution to conditions sufficient to reach a steady state between the fluid milk fraction and dissolved CO2. The patented method is said to be adapted for consumer dairy products of a wide variety, increasing shelf-life to about 45 to about 60 days.
The interaction between HPP and CO2 and their effects on food spoilage enzymes and microorganisms were described by Corwin and Shellhammer in Journal of Food Science 2002; 67: 697-701, entitled “Combined carbon dioxide and high pressure inactivation of pectin methylesterase, polyphenol oxidase, Lactobacillus plantarum and Escherichia coli.” The enzymes studied were pectin methylesterase (PME) and polyphenol oxidase (PPO) and the microorganisms studied were Lactobacillus plantarum ATCC 8014 (L. plantarum), an acid tolerant, lactic acid producing, non-spore forming, Gram positive bacterium, and Escherichia coli K12 (E. coli), an acid sensitive, non-spore forming, Gram negative bacterium. The objective of the study was to determine the effect of CO2 on increasing the efficacy of pressure processing to inactivate enzymes and microorganisms. CO2 was added at approximately 0.2 molar % to solutions processed at 500 to 800 MPa in order to further inactivate PME, PPO, L. plantarum, and E. coli. A significant interaction was found between CO2 and pressure at 25° C. and 50° C. for PME and PPO, respectively. Activity of PPO was said to be decreased by CO2 at all pressure treatments. Survival of L. plantarum was said to be decreased by the addition of CO2 at all pressures and the combination of CO2 and high pressure had a significant interaction. CO2 was said not to have a significant effect on the survival of E. coli under pressure.
U.S. Pat. No. 7,041,327 B2 to Hotchkiss et al., issued May 9, 2006, entitled “Carbon dioxide as an aid in pasteurization”, describes processes to inhibit or reduce the growth of bacteria and other pathogens in a liquid by adding CO2 to the liquid, and thermally inactivating the bacteria and other pathogens, so that the CO2 enhances the thermal inactivation process. The process is said to be applicable to a wide variety of fluids, liquids, semi-solids and solids. Prior to or simultaneously with thermal inactivation CO2 is added to the product by sparging or bubbling, preferably to obtain levels of about 400-2000 ppm. At this level of CO2, the amount of microbial death that occurs during heating in a normal pasteurization (HTST) process is said to be increased by 10% to 90% over thermal inactivation carried out without the addition of CO2 prior to the thermal inactivation step. After completion of the thermal inactivation process, the free CO2 is said to be removed.
Protein precipitation and separation out of proteins in protein beverages during manufacturing, shipping, and storage, may be compounded when the beverage contains an additional component, such as juice. Methods are known in the art for attempting to overcome the precipitation of protein from juice beverages. However, most of these methods involve the use of stabilizers.
Fiber or other carbohydrates may be added as a protein stabilizing agent, such as pectin, cellulose gum, xanthan gum, gum arabic, carageenan, guar gum, dextrin, cyclodextrin such as α-cyclodextrin (cyclohexaamylose, CAS No. 10016-20-3), maltodextrin such as FIBERSOL® soluble dietary fiber products, VITASUGAR™ brand fiber (Bio Neutra, Edmonton, Canada), dextrose monohydrate, and polydextrose. While stabilizers can help prevent protein precipitation, they may have the disadvantage of increasing the viscosity of the drink due to cross-linking with naturally present calcium cations. This increased viscosity may be undesirable as it may lead to a beverage having poor organoleptic properties for at least some applications. The range of amount of stabilizer which may be used may be quite narrow. For example, at a pectin concentration of below 0.06% by weight, sedimentation may be a significant problem, whereas above it, the viscosity of the beverage may be undesirably high. The ideal amount of stabilizer must be experimentally determined for each beverage formula, and may need to be adjusted from one batch to the next. Thus, a beverage formula which does not include a protein stabilizer but generates a beverage with good protein solubility is desirable for many applications.
U.S. Pat. No. 7,101,585 B2, to Shen et al., issued Sep. 5, 2006, entitled: “Ultra High Pressure Homogenization Process for Making a Stable Protein Based Acid Beverage” describes a process for preparing a stable suspension of an acid beverage, wherein a hydrated protein stabilizing agent (A) and a flavoring material (B) are combined as a preblend (I) and combined with either a slurry of a homogenized protein material (C) or a homogenized preblend (II) of a hydrated protein stabilizing agent (A) and a slurry of a protein material (C) to form a blend and pasteurizing and homogenizing the blend. The homogenization of the blend is carried out in two stages comprising a high pressure stage of from 8000-30,000 pounds per square inch and a low pressure stage of from 300-1,000 pounds per square inch. The acid beverage composition has a pH of from 3.0 to 4.5. This beverage contains juice, but is not carbonated. Pectin is added as a stabilizer.
Published Patent Application US 2003/0099753 A1 of Yang, published May 29, 2003, describes a fruit juice based beverage composition containing a protein selected from the group consisting of whey protein isolate and a combination of whey protein isolate and whey protein hydrolysate; a carbohydrate selected from the group consisting of sucrose, fructose, high fructose corn syrup 42 (HFCS 42), HFCS 55, combination of sucrose, fructose, HFCS 42, and HFCS 55, and combinations of maltodextrin with another carbohydrate selected from the group consisting of sucrose, fructose, HFCS 42, and HFCS 55; an edible acid selected from the group consisting of citric acid, phosphoric acid, combinations of citric acid and phosphoric acid, and combinations of malic acid with another edible acid selected from the group consisting of citric acid and phosphoric acid; a fruit juice or combinations of fruit juices; various vitamins and minerals; and optional fibers and flavors and a process for making such composition. The composition containing the above ingredients are asserted to be clear, have a pH of about 4.0 or less, and have a viscosity of less than about 40 centipoises. Protein stabilizing agents are used, including pectin.
U.S. Pat. No. 4,478,858 to Dahlen et al., issued Oct. 23, 1984, entitled: “Protein containing fruit drink and process for the manufacture thereof”, discloses a protein containing fruit juice drink comprising a fruit juice portion of 10-85% containing a citrus juice portion, a milk raw material portion of 90-15% by weight in which the milk raw material portion comprises whey proteins in an amount of 0.5-10% by weight of the finished product, and, as a sweetener, a hydrolyzed lactose, made of substantially pure lactose prepared from whey or a permeate from ultrafiltration of milk or whey, containing pure glucose and galactose derivative, which is alleged to act as a binder of the protein even in fruit drinks containing a citrus juice portion. The fruit drink may be manufactured in a concentrated form from a protein concentrate, concentrated fruit juice and/or fruit aromas and a concentrated hydrolysed lactose. A polysaccharide containing stabilizer may be added to the concentrate.